Pulpers



Jan. 28, 1964 A. G. SANDISON PULPERS 2 Sheets-Sheet 1 Filed Oct. 25. 1961 Jan. 28, 1964 A. vcs. SANDISON 3,119,570

PULPERS Filed Oct. 25. 1961 2 Sheets-Sheet 2 United States Patent 3,119,570 PULE'ERS Alexander Greswolde Sandison, Owen Sound, Ontario, Canada (PA). Box 942, Sidney, British Columbia, Canada) Filed Oct. 23,. 1961, Set. No. 146,988 1 Claims. (Cl. 241-73) This invention relates to pulpers of the type used for the re-pulping of laps, waste paper, and the like.

It has been common practice in pulpers to employ equipment including a pulper disc and also a perforated screen element for the extraction of material that has been broken down in size, but, in general, it has been found difficult to maintain continuous operation with perforations of size small enough to prevent passage of flakes or undefibered material of undesirably large size, as blockage of perforations is liable to occur if the perforations are of small size.

An object of the present invention is to provide a pulper of such construction that extraction may be obtained through a screen element having relatively small perforations. In the present invention the screen element is so located that the semi-disintegrated pulp is swept across it as substantially the maximum velocity imparted by the pulper disc, and the passage between the screen element and the main reservoir or tub of the pulper is so restricted that the surface of the screen element is pres.- surized under the centrifugal action of the pulper disc. In the preferred form of the invention the screening action is augmented by provision of means for producing pulsations of pressure across the screen element.

The preferred form of the invention is exemplified in the accompanying drawings whereof:

FIG. 1 is an elevation of the pulper disc and extraction equipment, chiefly in section.

FIG. 2 is a sectional elevation on the line 2-2 of FIG. 1.

FIG. 3 is a fragmentary elevation on the line 33 of FIG. 1.

IIllgIG. 4 is a fragmentary elevation on the line 4-4 of FIG. 5 is a diagrammatic plan view on a reduced scale, to show the direction of circulation in the pulper tub.

In the drawings, directions of movement are indicated by arrows. Small constructional details of conventional type, such as nuts and other fastenings, have been ornitted for clear-ness.

Referring to the drawings, a pulping disc is mounted on a shaft 11 which is rotatably mounted in bearings 12 held in a housing 13, and is provided with a drive pulley 14 and sealed by a stuffing box 15. The pulper disc preferably consists of a plate having its periphery formed with serrations 16, the serrations being bent to project beyond the plane of the disc. The disc may also be provided with projections 17 secured to its face. A fixed perforated screen element 18 of the for-m of a surface of revolution, and preferably of cylindrical form, is located loo-axial to the pulper disc, and a ring 19 connects between the interior of the screen element .18 and a tub 20 which holds the greater part of the material being processed and is preferably shaped as shown in FIG. 5 so as to provied suitable paths of flow for a divided circulation. The ring 19 is provided with helically located guide ribs 21 designed to direct the flow produced by the disc into horizontal streams, one stream emerging from the upper and one from the lower portion of the ring, so as to produce a flow pattern in the tub of the type shown in FIG. 5. The screen element 18 is surrounded by a casing 22 provided with a neck 23 leading to an outlet 24. A vane 25 located in the neck 23 is mounted on the shaft 26 3,119,570 Patented Jan. 28, 1964 Which is sealed by a stuffiing box 27 and is pivotally mounted in bearings 28 supported by a fixed housing 29. An arm 30 is mounted on the end of shaft 27 and is connected by a connecting rod 31 to a crank 32 carried in the end of shaft 11. Clearance passages 33 are provided between the vane 25 and the neck 23.

It will thus be seen that the pulper disc 10 is not directly located in the tub 20, as is common in pulpers, but instead is located in a pocket whose periphery consists chiefly of the screen element 18, and which connects to the tub through the ring 19.

In operation, the disc 10 is rotated by means of a motor and belt drive operating on pulley 14, and the disc produces a vortical circulation within the periphery of the pocket in which it is located, so that the main flow of material enters from the tub through the middle of ring 19 and is given a high vortical or tangential velocity by the action of the disc 10 and then sweeps at high velocity across the surface of the screen element 18 and out through the ring 19. The centrifugal action produced by the disc, in conjunction with the restriction to outflow imposed by ring 19, causes increased pressure over the interior surface of the screen element 18, and a proportion of the flow carrying material of sufliciently small size to be accepted by the screen perforations passes through the screen element into casing 22 and thence through neck 23 to outlet 24. The effect of the guide ribs 21 is to direct the surplus flow into the tub in two separate streams or jets, thus promoting the flow pattern in the tub 20 as shown in FIG. 5.

It will be understood that coarse material is broken up by the action of the projections 17 and serrations 16 of the pulper disc 10, but that material that has not been disintegrated sufficiently to pass through the perforations of the screen element 18 re-circulates into the tub and in course of time is drawn again into the zone of the pulping action of the disc. The serrations 16 are preferably bent over by unequal amounts, as illustrated, so as to present a staggered pattern comparable to the setting of the teeth of a saw. By adjusting the amount of set of the serrations the power absorption of the disc can be changed if so desired.

As the disc rotates the vane 25 is oscillated by means of the shaft 26, arm 30, connecting rod 31, and crank 32. The effect of this oscillation is to produce pulsation of pressure in casing 22 to assist in keeping the perforations of. screen element 18 from becoming blocked. The outflow of stock is through the passages 33 and these must be of sufiicient size not to restrict the outflow unduly, but must not be so large as to render ineffective the pulsating effect produced by the oscillation of the vane. In some cases it may be desirable to provide for adjustment of the extent of movement of the vane, and any wellknown mechanical movement for this purpose, such as those used for adjustment of valve travel in steam engines, may be employed.

What I claim as my invention is:

l. A pulper comprising a tub having a substantially vertical wall, a pocket located on the side of the wall, a power-driven pulping disc located within the pocket and having a substantially horizontal axis of rotation, a screen element of the form of a surface of revolution co-axial with the pulping disc and located within the pocket, an outlet for accepted material connecting to the exterior of the screen element, and a connection between the interior of the screen element and the tub, the connection being provided with flow-guiding means to direct the peripheral vortical flow induced by the pulping disc into at least one jet tangential to the wall of the tub.

2. A pulper, as claimed in claim 1, wherein the guid- 3 ing means extends inward to a radius less than that of the screen element.

3. A pulper, as claimed in claim 1, wherein the guiding means comprises at least one guide rib extending inward to a radius less than that of the screen element and located adjacent to the Wall of the tub to direct the peripheral vortical flow into at least one jet substantially horizontal and tangential to the wall of the tub.

4. A pulper comprising a tub, a power-driven pulping disc, a screen element of the form of a surface of revolution co-axial with the pulping disc, and a casing surrounding the screen element and provided with an outlet for accepted material that has passed through the screen element, the interior of the screen element being connected to the interior of the tub by an opening defined by restrictive bathing means extending inwardly to a radius less than the radius of the screen element so that circulation promoted by the centrifugal action of the disc is sufliciently restricted in the region of return outflow to the tub to cause substantial centrifugal pressure to be exerted on the inner surface of the screen element; said baffling means being provided with at least one substantially tangential passage directing the return outflow into the tub to form at least one high velocity jet to promote circulation within the tub.

5, A pulper, as claimed in claim 4, wherein said baffling means comprises at least one guide rib substantially in the form of a helix co-axial with the screen element and located adjacent to the wall of the tub to direct the return outflow in a tangential direction along the wall of the tub.

References Cited in the file of this patent UiJITED STATES PATENTS 1,951,684 Wells Mar. 20, 1934 2,434,449 Wells Jan. 13, 1948 2,537,570 Bossert Jan. 9, 1951 2,641,971 Ellis June 16, 1953 2,661,666 Knoll Dec. 8, 1953 2,665,853 Nicholson Jan. 12, 1954 2,682,810 Jones July 6, 1954 2,796,807 Sanford June 25, 1957 2,832,548 Hammes Apr. 29, 1958 3,021,080 Chaplin Feb. 13, 1962 FOREIGN PATENTS 500,552 Germany June 23, 1930 

1. A PULPER COMPRISING A TUB HAVING A SUBSTANTIALLY VERTICAL WALL, A POCKET LOCATED ON THE SIDE OF THE WALL, A POWER-DRIVEN PULPING DISC LOCATED WITHIN THE POCKET AND HAVING A SUBSTANTIALLY HORIZONTAL AXIS OF ROTATION, A SCREEN ELEMENT OF THE FORM OF A SURFACE OF REVOLUTION CO-AXIAL WITH THE PULPING DISC AND LOCATED WITHIN THE POCKET, AN OUTLET FOR ACCEPTED MATERIAL CONNECTING TO THE EXTERIOR OF THE SCREEN ELEMENT, AND A CONNECTION BETWEEN THE INTERIOR OF THE SCREEN ELEMENT AND THE TUB, THE CONNECTION BEING PROVIDED WITH FLOW-GUIDING MEANS TO DIRECT THE PERIPHERAL VORTICAL FLOW INDUCED BY THE PULPING DISC INTO AT LEAST ONE JET TANGENTIAL TO THE WALL OF THE TUB. 